Secondary battery

Abstract

To provide a technique for uniformly cooling an entire secondary battery in the secondary battery.SOLUTION: A secondary battery comprises: a case; a plurality of battery cells stored inside of the case and disposed in parallel in a horizontal direction; a heat medium which cools the battery cells; a gas circulation part in which the heat medium of a gas is circulated, the gas circulation part being disposed between two battery cells adjacent to each other; a liquid circulation part which is formed from a porous body and in which the heat medium of a liquid is circulated, the liquid circulation part being disposed between the gas circulation part and the battery cells and in contact with surfaces of the battery cells; and a heat exchange part which is disposed on an upper side of the gas circulation part in a vertical direction and liquefies the heat medium of the gas exhausted from the gas circulation part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a secondary battery. [Background technology]

[0002] BACKGROUND ART Chargeable and dischargeable secondary batteries have been known for some time (for example, Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-116092 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-146298 [Patent Document 3] Japanese Patent Application Publication No. 2023-37122 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-177935 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even with the prior art such as Patent Documents 1 to 4, there is still room for improvement in the technology for uniformly cooling the entire secondary battery.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a technique for uniformly cooling the entire secondary battery in a secondary battery. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following aspects.

[0007] (1) According to one aspect of the present invention, there is provided a secondary battery comprising: a case, a plurality of battery cells housed inside the case and arranged side by side in a horizontal direction, a heat transfer medium for cooling the battery cells, a gas circulation portion through which the heat transfer medium in a gaseous form flows and disposed between two adjacent battery cells, a liquid circulation portion formed of a porous body through which the heat transfer medium in a liquid form flows, the liquid circulation portion being disposed between the gas circulation portion and the battery cells and in contact with surfaces of the battery cells, and a heat exchange portion disposed vertically above the gas circulation portion and liquefying the heat transfer medium in a gaseous form discharged from the gas circulation portion.

[0008] According to this configuration, the liquid circulation section in contact with the surface of the battery cell is formed of a porous material, and the liquid heat transfer medium moves by capillary action. The heat transfer medium vaporized in the liquid circulation section by the heat of the battery cell passes through the gas circulation section and is discharged from the vertically upper side of the gas circulation section. The gaseous heat transfer medium discharged from the gas circulation section is liquefied in the heat exchange section located vertically above the gas circulation section. The liquefied heat transfer medium moves again through the liquid circulation section and is used to cool the battery cell. In this way, the battery cell is cooled by utilizing the phase change of the liquid heat transfer medium moving through the liquid circulation section. This allows the entire secondary battery to be cooled more uniformly than when the phase change of the heat transfer medium occurs partially due to the contact state between the heat transfer medium and the battery cell, etc.

[0009] (2) In the secondary battery of the above aspect, the liquid circulation section is disposed between each of the two adjacent battery cells and a gas circulation section disposed between the two battery cells. The secondary battery may further include a first reservoir for storing a liquid heat transfer medium, the first reservoir being sandwiched between the pair of liquid circulation sections vertically below the gas circulation section. The first reservoir may be formed of a porous material and connected to a vertically lower end of the liquid circulation section. According to this configuration, the first reservoir, which is sandwiched between the pair of liquid circulation sections and disposed vertically below the gas circulation section, stores the liquid heat transfer medium circulating through the liquid circulation section that is not vaporized by the heat of the battery cells. When the temperature of the battery cells rises and the amount of heat transfer medium moving through the liquid circulation section decreases, the liquid heat transfer medium stored in the first reservoir moves through the liquid circulation section by capillary action. This allows the battery cells to be further cooled.

[0010] (3) In the secondary battery of the above aspect, the plurality of battery cells, the gas circulation part, and the liquid circulation part form a battery stack, and the secondary battery further includes: a support part that supports the battery stack inside the case so that the battery stack is spaced apart from a bottom and a side surface of the case; a second storage part that stores a liquid heat medium, the second storage part being formed by the bottom and the side surface of the case on the vertically lower side of the battery stack; and a heating part that heats the liquid heat medium stored in the second storage part to generate a gaseous heat medium, and the gas circulation part has a groove that discharges a portion of the liquid heat medium stored in the first storage part to the second storage part, and the gaseous heat medium generated in the second storage part passes between the battery stack and the side surface of the case and moves vertically upward of the battery stack to be liquefied by the heat exchange part, and the heat medium liquefied by the heat exchange part may flow through the liquid circulation part. According to this configuration, the second storage section, formed by the bottom and side surfaces of the case on the vertically lower side of the battery stack, stores the liquid heat transfer medium that cannot be stored in the first storage section via the grooves in the gas flow section. When the amount of liquid heat transfer medium flowing through the liquid flow section is insufficient to sufficiently cool the battery cells, the liquid heat transfer medium stored in the second storage section is heated to generate a gaseous heat transfer medium in the second storage section. The gaseous heat transfer medium generated in the second storage section passes between the battery stack and the side surface of the case and moves vertically upward of the battery stack, where it is liquefied by the heat exchange section. This increases the amount of liquid heat transfer medium flowing through the liquid flow section. This prevents the heat transfer medium from being depleted in the liquid flow section, thereby further cooling the battery cells.

[0011] (4) The secondary battery of the above aspect may include a plurality of the first storage sections, and the secondary battery may further include a connection section formed of a porous body and connected to the vertically lower end of each of the plurality of first storage sections. According to this configuration, the connection section formed of a porous body connects to the vertically lower end of each of the plurality of first storage sections, which are also formed of a porous body. This allows the liquid heat medium stored in one of the plurality of first storage sections to move to the other first storage sections via the connection section by capillary action. This allows the liquid heat medium to be distributed relatively evenly to each of the plurality of first storage sections, thereby preventing depletion of the liquid heat medium in some of the first storage sections and in the liquid circulation section connected to those first storage sections. This allows the entire secondary battery to be cooled uniformly.

[0012] (5) In the secondary battery of the above aspect, the gas circulation portion may have a generally plate-like shape, and a pair of main surfaces may each have a convex portion formed on one of the main surfaces, the convex portion contacting the liquid circulation portion. A concave portion may be formed on one of the main surfaces at the position where the convex portion is formed on the other main surface, and a concave portion may be formed on one of the main surfaces at the position where the convex portion is formed on the other main surface. The interior of the concave portion formed on one of the main surfaces may be vertically connected to the interior of the concave portion formed on the other main surface. According to this configuration, the generally plate-like gas circulation portion has a convex portion and a concave portion formed on each of the pair of main surfaces. As a result, when the heat transfer medium liquefied by the heat exchange portion falls from above in the vertical direction into the gas circulation portion, it is retained in the convex portion. The liquid heat transfer medium retained in the convex portion moves to the liquid circulation portion and is used to cool the battery cells. Furthermore, in the gas circulation portion, the interior of the concave portion formed on one of the main surfaces is vertically connected to the interior of the concave portion formed on the other main surface. As a result, the heat transfer medium vaporized by the heat of the battery cells passes through the inside of the recess and is discharged from the vertically upper side of the gas flow section, making it easier to liquefy in the heat exchange section, thereby enabling efficient cooling of the battery cells.

[0013] (6) In the secondary battery of the above aspect, the battery cell may have a substantially rectangular parallelepiped shape, and the liquid circulation part may be in contact with the surface having the largest area among a plurality of surfaces of the battery cell. According to this configuration, the liquid circulation part is in contact with the surface having the largest area of ​​the substantially rectangular parallelepiped battery cell. This increases the amount of liquid heat transfer medium in the liquid circulation part in contact with the surface of the battery cell, thereby enabling efficient cooling of the battery cell.

[0014] (7) In the secondary battery of the above aspect, the heat exchange unit may include a refrigerant flow section through which a refrigerant supplied from an external source flows and a spacer in contact with the refrigerant flow section. The spacer may be disposed vertically above the gas flow section and include a flow path forming section that forms a heat medium flow path through which the gaseous heat medium flows, and a wall section formed of a porous material that is in contact with the refrigerant flow section and liquefies the gaseous heat medium passing through the heat medium flow path. According to this configuration, the heat exchange unit includes a spacer in contact with the refrigerant flow section through which the refrigerant flows. The spacer has a wall section formed of a porous material. The wall section is in contact with the refrigerant flow section and liquefies the gaseous heat medium passing through the heat medium flow path. This allows the gaseous heat medium to be efficiently liquefied, and the liquefied heat medium can be absorbed by the wall section formed of a porous material.

[0015] (8) The secondary battery of the above aspect may include a plurality of the liquid circulation sections, and the secondary battery may further include an intermediate section formed of a porous body and disposed between the heat exchange section and the plurality of the liquid circulation sections, the intermediate section being in contact with a vertically lower end of the wall section of the spacer and a vertically upper end of each of the plurality of the liquid circulation sections, and having an opening formed vertically above the gas circulation section and communicating with the heat medium flow path. According to this configuration, the intermediate section is formed of a porous body and in contact with the wall section of the spacer and each of the plurality of the liquid circulation sections. This allows the liquid heat medium recovered by the wall sections to move to the plurality of the liquid circulation sections via the intermediate section, thereby preventing depletion of the liquid heat medium in some of the liquid circulation sections.

[0016] (9) In the secondary battery of the above aspect, the gas flow part may be made of an insulating material. With this configuration, the gas flow part disposed between two adjacent battery cells is made of an insulating material, which can suppress an electrical short circuit between the two battery cells.

[0017] The present invention can be realized in various forms, such as a temperature adjustment device for a secondary battery, a cooling device for a secondary battery, a temperature adjustment method for a secondary battery, a system including a secondary battery, a control method for these devices and systems, a computer program for causing these devices and systems to perform charging and discharging, a server device for distributing the computer program, and a non-transitory storage medium on which the computer program is stored. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram showing a schematic configuration of a battery system according to a first embodiment. [Figure 2] FIG. 1 is a first cross-sectional schematic view of a secondary battery according to a first embodiment; [Figure 3] FIG. 2 is a second cross-sectional view of the secondary battery of the first embodiment; [Figure 4] FIG. 3 is an enlarged view of the α portion of FIG. 2. [Figure 5] FIG. 3 is a cross-sectional view taken along line CC in FIG. 2. [Figure 6] FIG. 3 is a cross-sectional view taken along line DD in FIG. 2. [Figure 7] FIG. 3 is a cross-sectional view taken along the line EE in FIG. 2. [Figure 8] FIG. 8 is an enlarged view of the β portion of FIG. [Figure 9] FIG. 3 is a cross-sectional view taken along the line FF in FIG. 2. [Figure 10] FIG. 10 is an enlarged view of the γ portion of FIG. 9. [Figure 11] FIG. 10 is a first diagram illustrating the function of the grooves in the gas flow portion. [Figure 12] FIG. 10 is a second diagram illustrating the function of the grooves in the gas flow portion. [Figure 13] 4A and 4B are diagrams illustrating the function of a gas flow section. [Figure 14] FIG. 10 is a diagram illustrating a first modified example of the gas flow portion. [Figure 15] FIG. 10 is a diagram illustrating a second modified example of the gas flow portion. DETAILED DESCRIPTION OF THE INVENTION

[0019] First Embodiment FIG. 1 is a schematic diagram showing the general configuration of a battery system 100 including a secondary battery 1 according to a first embodiment. The battery system 100 of this embodiment includes the secondary battery 1, a heat exchanger 6 capable of supplying a refrigerant to the secondary battery 1, a pump 7 for pressurizing the refrigerant, and a refrigerant flow path 8 connecting the secondary battery 1, the heat exchanger 6, and the pump 7. The battery system 100 stores electricity supplied from a power supply unit such as an external power source (not shown) in the secondary battery 1 and supplies the stored electricity to a power consuming unit such as an external motor (not shown) as needed. The heat exchanger 6 supplies a refrigerant used to cool a heat medium included in the secondary battery 1 to the secondary battery 1 via the refrigerant flow path 8. In FIG. 1, the vertical direction of the secondary battery 1 is designated as the z-axis direction, the direction along which the refrigerant flow path 8 connects to the secondary battery 1 is designated as the y-axis direction, and the direction perpendicular to the y-axis and z-axis is designated as the x-axis direction.

[0020] FIG. 2 is a first schematic cross-sectional view of the secondary battery 1 of this embodiment. FIG. 3 is a second schematic cross-sectional view of the secondary battery 1 of this embodiment. FIG. 4 is an enlarged view of the α portion of FIG. 2. FIG. 2 is a schematic cross-sectional view of the secondary battery 1 shown in FIG. 1 taken along line AA, perpendicular to the y-axis. FIG. 3 is a schematic cross-sectional view of the secondary battery 1 shown in FIG. 1 taken along line BB, perpendicular to the x-axis. For ease of explanation, FIGS. 2 and 3 are not exact cross-sectional views of the secondary battery 1, but are schematic cross-sectional views. Therefore, the thickness and size of each part shown in FIGS. 2 and 3 differ from the actual thickness and size. The secondary battery 1 of this embodiment includes a case 10, a plurality of battery cells 20, a plurality of gas flow sections 30, a plurality of liquid flow sections 40, and a heat exchange section 60.

[0021] The case 10 has a substantially rectangular parallelepiped shape and houses a plurality of battery cells 20, a plurality of gas flow sections 30, a plurality of liquid flow sections 40, a heat exchange section 60, and the like. A heat medium for cooling the battery cells 20 is sealed inside the case 10. In this embodiment, the heat medium is a material that can change phase from liquid to gas due to heat generated in the battery cells 20, such as a low-boiling-point fluorocarbon-based medium. The heat medium does not have to be sealed inside the case 10; for example, the amount of heat medium used may be increased or decreased in an external heat medium supply source.

[0022] The battery cells 20 are, for example, lithium ion batteries. In this embodiment, the battery cells 20 have a substantially rectangular parallelepiped shape. The multiple battery cells 20 are housed inside the case 10 and arranged side by side in the horizontal direction. Specifically, in the secondary battery 1 of this embodiment, five battery cells 20 are arranged side by side in the x-axis direction (see FIG. 2). An insulating film (not shown) is applied to the battery cells 20.

[0023] A gas heat transfer medium flows through the gas flow section 30. In this embodiment, the gas flow section 30 has a first gas flow section 31 and a second gas flow section 32. The first gas flow section 31 is a substantially flat plate-shaped member and is disposed between two adjacent battery cells 20 as shown in FIG. 4. The second gas flow section 32, like the first gas flow section 31, is a substantially flat plate-shaped member and is disposed outside the outermost battery cell 20a of the multiple battery cells 20 arranged side by side inside the case 10 as shown in FIG. 4. The gas flow section 30 is made of an insulating material to prevent short-circuiting between adjacent battery cells 20. The detailed configuration of the gas flow section 30 will be described later.

[0024] The liquid circulation section 40 is formed of a porous body, through which the liquid heat transfer medium flows. Examples of porous bodies that form the liquid circulation section 40 include sintered bodies of nickel, copper, aluminum, etc., sintered bodies of stainless steel fibers, sintered ceramic bodies, sintered resin bodies, and fiber cloth. The liquid circulation section 40 of this embodiment is formed of a porous body made of metal. In the liquid circulation section 40, the liquid heat transfer medium moves mainly by capillary action within the porous body. The liquid circulation section 40 of this embodiment includes a first liquid circulation section 41, a second liquid circulation section 42, and a third liquid circulation section 43. The first liquid circulation section 41 is disposed between the first gas circulation section 31 and the battery cell 20, and is in contact with the surface 21 with the largest area among the multiple surfaces of the battery cell 20, which has a substantially rectangular parallelepiped shape. The second liquid circulation part 42 is disposed between the outermost battery cell 20a among the plurality of battery cells 20 and the second gas circulation part 32, and is in contact with the outer surface 21a of the battery cell 20a. The third liquid circulation part 43 is disposed outside the second gas circulation part 32 when viewed from the battery cell 20a.

[0025] The first storage section 50 stores a liquid heat transfer medium. The first storage section 50 is disposed vertically below each of the plurality of gas circulation sections 30, sandwiched between a pair of liquid circulation sections 40. In this embodiment, the secondary battery 1 includes a plurality of first storage sections 50. The first storage sections 50 are formed of a porous body, and as shown in FIG. 4 , are connected to any two of the vertically lower ends 41 a, 42 a, 43 a of the liquid circulation sections 40. The porous body forming the first storage sections 50, like the porous body forming the liquid circulation section 40, is made of a sintered body of nickel, copper, aluminum, or the like, a sintered body of stainless steel fiber, a sintered ceramic body, a sintered resin body, a fiber cloth, or the like.

[0026] As shown in FIGS. 2 and 4 , the connection member 51 is connected to the vertically lower end 50a of each of the multiple first storage sections 50. The connection member 51 is formed, for example, from a porous body made of the same material as the porous body that forms the first storage sections 50. In the connection member 51, the liquid heat transfer medium stored in each of the multiple first storage sections 50 moves by capillary action. This allows the liquid heat transfer medium to be distributed relatively evenly to each of the multiple first storage sections 50, thereby preventing depletion of the liquid heat transfer medium in some of the first storage sections 50 or in the liquid circulation sections 40 connected to the first storage sections 50.

[0027] In this embodiment, the plurality of battery cells 20, the plurality of gas flow sections 30, and the plurality of liquid flow sections 40 are stacked along the x-axis direction, as shown in Fig. 2. The stacked plurality of battery cells 20, the plurality of gas flow sections 30, and the plurality of liquid flow sections 40 are sandwiched between two end plates 11. Here, an assembly of the plurality of battery cells 20, the plurality of gas flow sections 30, the plurality of liquid flow sections 40, the two end plates 11, the plurality of first reservoirs 50, and the connection member 51 is referred to as a battery stack 1a.

[0028] In the secondary battery 1 of this embodiment, the battery stack 1a is fixed in position inside the case 10 by a connection flow path 9 that supplies the refrigerant flowing through the refrigerant flow path 8 to a heat exchanger 60 (described later). Specifically, as shown in FIGS. 2 and 3 , the refrigerant flow section 61 supports the battery stack 1a inside the case 10 so that the battery stack 1a is spaced apart from the bottom surface 10a and the side surface 10b of the case 10. This allows the bottom surface 10a and the side surface 10b of the case 10 to store a liquid heat medium below the battery stack 1a in the vertical direction. Here, the inside of the case 10 formed by the bottom surface 10a and the side surface 10b of the case 10 is referred to as a second storage section 52.

[0029] Heater 12 is provided outside case 10 on bottom surface 10a of case 10. Under the control of a control unit (not shown), heater 12 heats the liquid heat medium stored in second storage section 52 (the inside of case 10 formed by bottom surface 10a and side surface 10b of case 10) to generate a gaseous heat medium.

[0030] 2, the heat exchanger 60 is disposed vertically above the plurality of gas flow sections 30. The heat exchanger 60 liquefies the gaseous heat medium discharged from the plurality of gas flow sections 30. The heat exchanger 60 includes a refrigerant flow section 61 through which the refrigerant supplied from the heat exchanger 6 flows, and a spacer 62 in contact with the refrigerant flow section 61. In this embodiment, the refrigerant supplied from the heat exchanger 6 is, for example, pure water, a mixture of pure water and ethylene glycol, a mixture of pure water and propylene glycol, ethylene glycol, propylene glycol, a fluorocarbon-based refrigerant, a natural refrigerant such as carbon dioxide, or an insulating fluid such as silicone oil.

[0031] FIG. 5 is a cross-sectional view taken along line CC in FIG. 2. FIG. 5 shows a cross-sectional view of the heat exchanger 60, including the x-axis and the y-axis. The refrigerant flow section 61 has two main flow paths 61a and 61b and a plurality of connection flow paths 61c connected to the main flow paths 61a and 61b, respectively. The main flow path 61a is a flow path in the refrigerant flow section 61 that allows the refrigerant supplied from the heat exchanger 6 to flow into the heat exchanger 60, and the main flow path 61b is a flow path in the refrigerant flow section 61 that allows the refrigerant to flow out from the heat exchanger 60 toward the heat exchanger 6. In this embodiment, the refrigerant flows mainly along the y-axis direction in the two main flow paths 61a and 61b (see FIG. 5). In the connection flow path 61c, the refrigerant flows along the x-axis direction from the main flow path 61a to the main flow path 61b. The connection flow path 61c is disposed between adjacent spacers 62.

[0032] The spacers 62 are arranged so as to be in contact with the connection flow path 61c. In this embodiment, three spacers 62 are arranged along the x-axis direction, and six spacers 62 are arranged along the y-axis direction. The spacers 62 have a flow path forming portion 62a and two wall portions 62b. The flow path forming portion 62a is arranged vertically above the gas flow portion 30. The flow path forming portion 62a forms a heat medium flow path 62c through which the heat medium in the form of gas passes. The heat medium in the form of gas that passes through the heat medium flow path 62c is discharged into the inside of the case 10 from an opening 62d formed at the upper end of the flow path forming portion 62a in the extension direction.

[0033] The wall portion 62b is a substantially plate-shaped member formed of a porous body. The two wall portions 62b are supported by the flow path forming portion 62a so as to sandwich the heat medium flow path 62c while being in contact with the connection flow path 61c. The two wall portions 62b liquefy the gaseous heat medium passing through the heat medium flow path 62c. The liquefied heat medium is absorbed by the wall portions 62b formed of a porous body or falls vertically downward.

[0034] The intermediate member 71 is disposed between the heat exchange unit 60 and the plurality of liquid circulation units 40 (see FIG. 2). The intermediate member 71 has a generally plate-like shape and is formed of a porous material. The intermediate member 71 contacts the vertically lower end of the wall 62b of the spacer 62 and the vertically upper end 41b, 42b, 43b of the liquid circulation unit 40 (see FIG. 4). As a result, the liquid heat medium absorbed by the wall 62b of the spacer 62 moves to the intermediate member 71 by capillary action. The intermediate member 71 also functions to receive the liquid heat medium that is liquefied in the heat medium flow path 62c and drops vertically downward. The liquid heat medium contained in the intermediate member 71 moves to the liquid circulation units 40 that are in contact with the intermediate member 71. As a result, the heat medium liquefied by the heat exchange unit 60 moves to the liquid circulation units 40. The intermediate member 71 has an opening 71a formed vertically above the gas flow section 30 and communicating with the heat medium flow path 62c of the spacer 62 (see FIG. 2). The gaseous heat medium moving through the gas flow section 30 passes through the opening 71a and flows into the heat medium flow path 62c.

[0035] As shown in Fig. 2, the distribution member 72 is disposed vertically above each of the plurality of battery cells 20 (see Fig. 2). The distribution member 72 has a hollow, approximately rectangular parallelepiped shape. As shown in Fig. 2, the distribution member 72 is disposed in a state sandwiched between a pair of liquid circulation sections 40.

[0036] The heat medium collecting unit 73 is provided around the battery stack 1a on the vertically upper side of the end plate 11 in contact with the intermediate member 71 (see FIGS. 2 and 3). The heat medium collecting unit 73 has a collecting unit 731 provided on the vertically upper side and a support unit 732 provided on the vertically lower side of the collecting unit 731. The collecting unit 731 is formed of a porous body and collects the heat medium that liquefies and falls vertically above itself. The liquid heat medium collected by the collecting unit 731 moves to the intermediate member 71 with which the collecting unit 731 is in contact. The support unit 732 supports the collecting unit 731. The support unit 732 is formed so as to move vertically downward as it approaches the battery stack 1a. This allows the liquid heat medium collected by the collecting unit 731 to move to the intermediate member 71. Support portion 732 also has the function of pressing collection portion 731 against intermediate member 71. A gap 730 is formed between heat medium collection portion 73 and case 10. Collection portion 731 corresponds to the "intermediate portion" in the claims.

[0037] The size of the combined portion of the intermediate member 71 and the heat medium collection unit 73 disposed outside the intermediate member 71 is desirably changed to match the sizes of the heat exchange unit 60 and the battery stack 1a. Specifically, when the heat exchange unit 60 and the battery stack 1a are viewed from the positive side in the z-axis direction, if the size of the heat exchange unit 60 is larger than that of the battery stack 1a or if the shape of the heat exchange unit 60 differs from that of the battery stack 1a, the size is desirably large enough to receive the liquid heat medium that liquefies and drops from the surface of the heat exchange unit 60. By setting the size in this way, the liquid heat medium that liquefies in the heat exchange unit 60 can be reliably collected and transferred to the liquid circulation unit 40.

[0038] FIG. 6 is a cross-sectional view taken along line DD in FIG. 2. FIG. 6 shows a cross-sectional view of the distributor 72, including the x-axis and y-axis. In the distributor 72, a portion of the liquid heat transfer medium contained in the intermediate member 71 passes through an opening 72a formed on the vertically upper side of the distributor 72 and falls to the inner side 72b of the distributor 72 (see FIG. 4). The liquid heat transfer medium that falls to the inner side 72b of the distributor 72 is held by the surface tension of the liquid heat transfer medium in an opening 72c (see FIG. 6) formed on the vertically lower side of the distributor 72. A portion of the liquid heat transfer medium held in the opening 72c moves from the surface 40b (see FIG. 6) of the liquid circulation portion 40 to the liquid circulation portion 40 by capillary action. As a result, the distributor 72 can move the liquid heat transfer medium that cannot be held by the intermediate member 71 and falls to the inner side 72b of the distributor 72 to the liquid circulation portion 40.

[0039] Fig. 7 is a cross-sectional view taken along line EE in Fig. 2. Fig. 8 is an enlarged view of part β in Fig. 7. Fig. 9 is a cross-sectional view taken along line FF in Fig. 2. Fig. 10 is an enlarged view of part γ in Fig. 9. Next, the detailed configuration of the gas flow section 30 will be described.

[0040] The cross-sectional view of the battery stack 1a shown in FIG. 7 is a cross-sectional view of a roughly central portion of the battery stack 1a, as shown in FIG. 2. As shown in FIG. 7, the battery stack 1a includes a plurality of battery cells 20, a plurality of gas flow sections 30, and a plurality of liquid flow sections 40 stacked by a pair of end plates 11. The enlarged view of section β in FIG. 7 shown in FIG. 8 shows a cross-section of the end of the gas flow section 30 in the y-axis direction. A rib 30a is formed at the end of the gas flow section 30 in the y-axis direction, and the end 40c of the liquid flow section 40 in the y-axis direction is closed by the rib 30a. In the battery stack 1a, the end of the gas flow section 30 in the y-axis direction has this shape in a portion of the battery stack 1a excluding the negative side in the z-axis direction. As a result, the liquid heat transfer medium moving through the liquid flow section 40 does not leak out from the side of the battery stack 1a in a portion of the battery stack 1a excluding the negative side in the z-axis direction.

[0041] The cross-sectional view of the battery stack 1a shown in Fig. 9 shows a cross-sectional view of the battery stack 1a on the negative side in the z-axis direction. On the negative side in the z-axis direction of the battery stack 1a, a groove 30b is formed at the end of the gas flow section 30 in the y-axis direction. As shown in Fig. 10, which is an enlarged view of the γ portion of Fig. 9, the groove 30b is formed so as to expose the end 40c of the liquid flow section 40 in the y-axis direction. This allows the battery stack 1a to discharge a portion of the liquid heat transfer medium contained in the liquid flow section 40 to the outside of the battery stack 1a via the groove 30b.

[0042] FIG. 11 is a first diagram illustrating the function of the grooves 30b of the gas flow section 30. FIG. 11 shows a perspective view of a portion of the gas flow section 30 where the grooves 30b are formed. The gas flow section 30 has a rib 30a formed on the outer periphery of the gas flow section 30, which has a storage hole 30c capable of accommodating the first storage section 50. As shown in FIG. 11, some of the ribs 30a are not formed, and these serve as the grooves 30b described in FIGS. 9 and 10. The gas flow section 30 of this embodiment is characterized by the relationship between the height at which the grooves 30b are formed and the height of the first storage section 50. Specifically, the bottom surface (the surface on the upper side in the z-axis direction) 30d of the rib 30a that forms the grooves 30b is formed at a position in the z-axis direction that is approximately the same height as or slightly lower than the top surface 30e of the storage hole 30c in which the first storage section 50 is accommodated.

[0043] 12 is a second diagram illustrating the function of groove 30b of gas flow section 30. FIG. 12 is a schematic cross-sectional view perpendicular to the x-axis of secondary battery 1, showing a cross-section passing through gas flow section 30. For example, in FIG. 12, the height in the z-axis direction of bottom surface 30d of rib 30a forming groove 30b is formed slightly lower than the height of top surface 30e of housing hole 30c in which first reservoir 50 is housed. As a result, when the amount of liquid heat transfer medium contained in first reservoir 50 increases, some of the liquid heat transfer medium contained in first reservoir 50 passes through groove 30b and is discharged to the outside of battery stack 1a (white arrow F1 shown in FIG. 12).

[0044] FIG. 13 is a diagram illustrating the function of the gas flow section 30. Next, the structure of the gas flow section 30 for passing a gaseous heat transfer medium will be described. The cross-sectional view of FIG. 13 shows a cross section including the x-axis and y-axis of the gas flow section 30 sandwiched between a pair of liquid flow sections 40. FIG. 13 illustrates the shapes of two portions of the gas flow section 30 that are at different positions (heights) along the z-axis. Specifically, portion 33, where the hatching intervals are relatively wide, indicates a portion that is at a higher position (closer) than portion 34, where the hatching intervals are relatively narrow.

[0045] In the gas circulation section 30 of this embodiment, a pair of main surfaces are each formed with a convex portion that comes into contact with a pair of liquid circulation sections 40. Furthermore, where the convex portion of one main surface is formed, a concave portion is formed in the other main surface, and where the convex portion of the other main surface is formed, a concave portion is formed in one main surface. Specifically, in the portion 33 of the gas circulation section 30, of the pair of main surfaces 331, 332, where the convex portion 331a of one main surface 331 is formed, a concave portion 332b is formed in the other main surface 332, and where the convex portion 332a of the other main surface 332 is formed, a concave portion 331b is formed in one main surface 331. In addition, in part 34 of the gas flow section 30, at the position where the convex portion 341a of one of the pair of main surfaces 341, 342 is formed on the other main surface 342, a concave portion 342b is formed, and at the position where the convex portion 342a of the other main surface 342 is formed, a concave portion 341b is formed on one of the main surfaces 341.

[0046] 13, in the gas flow section 30 of this embodiment, convex portions and concave portions are alternately formed in both the horizontal direction (the direction included in the plane including the x-axis and y-axis) and the vertical direction (the z-axis direction). As a result, when the gas flow section 30 is viewed vertically, the inside of the concave portion 331b communicates with the inside of the concave portion 341b, and the inside of the concave portion 332b communicates with the inside of the concave portion 342b. As a result, the gaseous heat transfer medium passing through the gas flow section 30 can move vertically upward by passing through the insides Sp of the concave portions 331b, 332b, 341b, and 342b that are communicated in the vertical direction.

[0047] Next, we will explain in detail the cooling function of the secondary battery 1. When the secondary battery 1 is not charging or discharging and, for example, the temperature of the battery cells 20 is around room temperature, the liquid heat medium is stored in each of the first storage section 50 and the second storage section 52. At this time, part of the liquid heat medium stored in the first storage section 50 moves to the liquid circulation section 40 in contact with the first storage section 50 due to the capillary phenomenon of the liquid in the porous body.

[0048] When the battery cell 20 is charged or discharged, the temperature of the battery cell 20 rises. When the temperature of the battery cell 20 rises, the temperature of the liquid heat medium contained in the liquid circulation part 40 that is in contact with the battery cell 20 also rises and the liquid heat medium vaporizes. The heat of vaporization of the heat medium at this time cools the battery cell 20. The vaporized heat medium moves from the liquid circulation part 40 to the gas circulation part 30, passes through the insides Sp of the recesses 331b, 332b, 341b, and 342b that the gas circulation part 30 has, and moves vertically upward of the gas circulation part 30.

[0049] The gaseous heat medium moving vertically upward in the gas flow section 30 passes through the opening 71a of the intermediate member 71 and flows into the heat medium flow path 62c of the spacer 62 of the heat exchange section 60. A portion of the gaseous heat medium flowing into the heat medium flow path 62c is cooled and liquefied by the wall portion 62b that contacts the connecting flow path 61c through which the refrigerant flows. The liquefied heat medium is absorbed by the wall portion 62b of the spacer 62 or falls vertically downward as droplets. The liquid heat medium absorbed by the spacer 62 passes through the intermediate member 71 and moves to the liquid flow section 40. The liquid heat medium that falls vertically downward as droplets is received by the intermediate member 71 and moves to the liquid flow section 40. The liquid heat medium that cannot be held by the intermediate member 71 falls into the inner side 72b of the distribution member 72. The liquid heat medium that drops onto the inner side 72b of the distributor 72 is held by the openings 72c of the distributor 72 and moves to the liquid circulation section 40, or drops through the openings 72c into the gas circulation section 30. The liquid heat medium that moves to the liquid circulation section 40 moves vertically downward, contributing again to the cooling of the battery cells 20, or moving to the first storage section 50. The liquid heat medium that drops into the gas circulation section 30 is held by the multiple protrusions 331a, 332a, 341a, and 342a of the gas circulation section 30, and moves to the liquid circulation section 40 that is in contact with the protrusions 331a, 332a, 341a, and 342a. The movement and phase change of the heat medium during cooling of the secondary battery 1 in this embodiment are as described above.

[0050] In the secondary battery 1 of this embodiment, the liquid heat medium can be stored in the first storage section 50 disposed vertically below the gas flow section 30 and in the second storage section 52 formed by the bottom surface 10a and side surface 10b of the case 10. As a result, when the temperature of the battery cells 20 begins to rise, the battery cells 20 can be cooled only by the liquid heat medium stored in the first storage section 50, making it possible to cool the battery cells 20 with a relatively small amount of heat medium. Therefore, the battery cells 20 can be cooled in a rapid response to temperature changes in the battery cells 20.

[0051] In the secondary battery 1 of this embodiment, if the temperature of the battery cells 20 further increases, the amount of liquid heat medium moving through the liquid circulation section 40 can be increased. Specifically, the liquid heat medium stored in the second storage section 52 is heated by the heater 12 to become a gaseous heat medium. The gaseous heat medium heated by the heater 12 rises between the battery stack 1a and the side surface 10b of the case 10 inside the case 10, passes through the gap 730 between the heat medium collector 73 and the case 10, and moves vertically upward inside the case 10. The gaseous heat medium that has moved vertically upward in the case 10 is liquefied on the surface of the heat exchange section 60, which has a relatively low temperature, and falls vertically downward as a liquid heat medium. The falling liquid heat medium is collected by the collection section 731 of the heat medium collector 73. The liquid heat transfer medium collected in the collection section 731 passes through the intermediate member 71 in contact with the collection section 731 and moves to the liquid circulation section 40 .

[0052] When the temperature of the battery cells 20 drops and cooling by the heat medium ceases, the amount of liquid heat medium stored in the first storage section 50 increases. When the amount of liquid heat medium stored in the first storage section 50 becomes too large to be stored in the first storage section 50, some of the liquid heat medium stored in the first storage section 50 is discharged from the battery stack 1a to the inside of the case 10 through the grooves 30b formed in the gas flow section 30. The liquid heat medium discharged to the outside of the battery stack 1a through the grooves 30b is stored in the second storage section 52.

[0053] The plurality of first reservoirs 50 are connected by connecting members 51, and each of the first reservoirs 50 and the connecting members 51 is formed of a porous body. As a result, the liquid heat medium moves to a portion where there is relatively little liquid heat medium due to capillary action of the liquid heat medium in the porous body between the plurality of first reservoirs 50 and the connecting members 51. Therefore, in the battery stack 1a, depletion of the liquid heat medium is suppressed, and uneven cooling of certain portions can be suppressed.

[0054] In the secondary battery 1 of this embodiment, from the vertically downward direction of the secondary battery 1, the connecting member 51, the multiple first reservoirs 50, the multiple liquid circulation sections 40, the intermediate member 71, the collection section 731, and the wall section 62b of the spacer 62 are each formed of a porous material. The connecting member 51 and the multiple first reservoirs 50 are in contact with each other, and the multiple first reservoirs 50 are in contact with the multiple liquid circulation sections 40. The multiple liquid circulation sections 40 are in contact with the intermediate member 71, the intermediate member 71 is in contact with the collection section 731, and the intermediate member 71 is in contact with the wall section 62b of the spacer 62. This allows the liquid heat transfer medium to move between these components by capillary action, thereby preventing the liquid heat transfer medium from being partially depleted, particularly in the multiple liquid circulation sections 40. Therefore, the entire secondary battery 1 can be uniformly cooled.

[0055] According to the secondary battery 1 of this embodiment described above, the liquid circulation section 40, which is in contact with the surfaces 21, 21a of the battery cells 20, is formed of a porous material. As a result, the liquid heat transfer medium moves in the liquid circulation section 40 due to capillary action. The heat transfer medium vaporized in the liquid circulation section 40 by the heat of the battery cells 20 passes through the gas circulation section 30 and is discharged from the vertically upper side of the gas circulation section 30. The gaseous heat transfer medium discharged from the gas circulation section 30 is liquefied in the heat exchange section 60, which is located vertically above the gas circulation section 30. The liquefied heat transfer medium moves again through the liquid circulation section 40 and contributes to cooling the battery cells 20. In this way, the battery cells 20 are cooled by the phase change of the liquid heat transfer medium moving through the liquid circulation section 40 to the gaseous heat transfer medium. As a result, the entire secondary battery 1 can be cooled more uniformly than when the phase change of the heat transfer medium occurs only partially due to the contact state between the heat transfer medium and the battery cells, etc.

[0056] Furthermore, according to the secondary battery 1 of this embodiment, the first storage section 50, which is sandwiched between the pair of liquid circulation sections 40 and disposed vertically below the gas circulation section 30, stores the liquid heat medium that flows through the liquid circulation section 40 and is not vaporized by the heat of the battery cells 20. As a result, when the temperature of the battery cells 20 rises and the amount of heat medium flowing through the liquid circulation section 40 decreases, the liquid heat medium stored in the first storage section 50 moves to the liquid circulation section 40 by capillary action, thereby cooling the battery cells 20.

[0057] Furthermore, according to the secondary battery 1 of this embodiment, the second storage section 52 formed by the bottom surface 10a and the side surface 10b of the case 10 on the vertically lower side of the battery stack 1a stores the liquid heat medium that cannot be stored in the first storage section 50 via the grooves 30b of the gas flow section 30. When the amount of liquid heat medium supplied from the first storage section 50 to the liquid flow section 40 is too small to sufficiently cool the battery cells 20, the liquid heat medium stored in the second storage section 52 is heated to generate a gaseous heat medium in the second storage section 52. The gaseous heat medium generated in the second storage section 52 passes between the side surface 10b of the case 10 and the battery stack 1a, moves vertically upward of the battery stack 1a, and is liquefied by the heat exchange section 60. This increases the amount of heat transfer medium in the liquid flowing through the liquid flow section 40, thereby preventing the heat transfer medium from running out in the liquid flow section 40 and ensuring that the battery cells 20 are cooled.

[0058] Furthermore, in the secondary battery 1 of this embodiment, the connecting member 51 formed of a porous body is connected to the vertically lower end 50a of each of the multiple first reservoirs 50, which are also formed of a porous body. This allows the liquid heat transfer medium stored in one of the multiple first reservoirs 50 to move to the other first reservoirs 50 via the connecting member 51 by capillary action. This allows the liquid heat transfer medium to be distributed relatively evenly among the multiple first reservoirs 50, thereby preventing depletion of the liquid heat transfer medium in some of the first reservoirs 50 and in the liquid circulation sections 40 connected to those first reservoirs 50. This allows the entire secondary battery 1 to be cooled more uniformly.

[0059] Furthermore, in the secondary battery 1 of this embodiment, the gas flow section 30, which has a generally plate shape, has convex portions 331a, 332a and concave portions 331b, 332b formed on each of the pair of main surfaces 331, 332, and has convex portions 341a, 342a and concave portions 341b, 342b formed on each of the pair of main surfaces 341, 342. The convex portions 331a, 332a, 341a, 342a are in contact with the pair of liquid flow sections 40, respectively. As a result, when the heat medium liquefied by the heat exchange section 60 falls from above in the vertical direction, it is retained by the convex portions 331a, 332a, 341a, 342a. The liquid heat medium retained in the convex portions 31a, 332a, 341a, 342a moves to the liquid flow section 40 and contributes to cooling of the battery cells 20. Furthermore, in the gas flow section 30, the inside of the recesses 331b, 341b formed on one of the main surfaces 331, 341 communicates with the inside of the recesses 332b, 342b formed on the other of the main surfaces 332, 342 in the vertical direction. As a result, the heat medium vaporized by the heat of the battery cells 20 passes through the inside of the recesses 331b, 332b, 341b, 342b and is discharged from the vertically upper side of the gas flow section 30, making it easier to liquefy the heat exchange section 60. This allows the battery cells 20 to be cooled efficiently.

[0060] Furthermore, in the secondary battery 1 of this embodiment, the liquid circulation part 40 contacts the surfaces 21, 21a of the battery cells 20, which have a substantially rectangular parallelepiped shape and have the largest area. This increases the amount of liquid heat transfer medium in the liquid circulation part 40 that contacts the surfaces 21, 21a of the battery cells 20, allowing the battery cells to be cooled efficiently.

[0061] Furthermore, according to the secondary battery 1 of this embodiment, the heat exchange unit 60 has a spacer 62 that is in contact with the refrigerant flow unit 61 through which the refrigerant flows. The wall 62b of the spacer 62 is formed of a porous body and is in contact with the refrigerant flow unit 61. As a result, in the spacer 62, the wall 62b cools and liquefies the gaseous heat medium passing through the heat medium flow path 62c. Therefore, the gaseous heat medium can be efficiently liquefied, and the wall 62b formed of a porous body can efficiently absorb the liquefied heat medium.

[0062] Furthermore, according to the secondary battery 1 of this embodiment, the intermediate member 71 is formed of a porous body and is in contact with the wall portion 62b of the spacer 62 and each of the plurality of liquid circulation portions 40. This allows the intermediate member 71 to transfer at least one of the liquid heat transfer medium absorbed by the wall portion 62b and the liquid heat transfer medium falling as droplets to any one of the plurality of liquid circulation portions 40. This makes it possible to prevent the liquid heat transfer medium from being depleted in some of the liquid circulation portions 40.

[0063] Furthermore, in the secondary battery 1 of this embodiment, the gas flow section 30 disposed between two adjacent battery cells 20 is made of an insulating material, which can prevent an electrical short circuit between the two battery cells 20.

[0064] Furthermore, in the secondary battery 1 of this embodiment, the liquid circulation part 40 is formed of a porous body made of metal. This makes it easier for heat from the battery cells 20 to spread throughout the liquid circulation part 40 by utilizing the thermal conduction of the metal that forms the porous body. This makes it easier for the liquid heat transfer medium contained in the liquid circulation part 40 to heat up, which makes it easier for a phase change to occur and improves cooling efficiency. This allows the battery cells 20 to be cooled efficiently.

[0065] <Modification of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0066] [Variation 1] In the above-described embodiment, the first storage section 50, which is disposed vertically below the gas circulation section 30, stores the liquid heat medium that flows through the liquid circulation section 40 and is not vaporized by the heat of the battery cells 20. The first storage section 50 may be omitted. By providing the first storage section 50 that stores the liquid heat medium, it is possible to supply the liquid heat medium to the liquid circulation section 40 when the amount of heat medium flowing through the liquid circulation section 40 decreases. This makes it possible to prevent the liquid heat medium from drying out in the liquid circulation section 40.

[0067] [Variation 2] In the above-described embodiment, the first storage section 50 and the second storage section 52 are provided as storage sections for storing the liquid heat medium. However, only the first storage section may be provided. By providing the second storage section 52 that can store the liquid heat medium that cannot be stored in the first storage section 50, the liquid heat medium can be supplied to the liquid circulation section 40 when the heat medium moving through the liquid circulation section 40 becomes low, thereby further preventing the heat medium from running out in the liquid circulation section 40.

[0068] [Variation 3] In the above-described embodiment, the connecting member 51 is formed of a porous body and is connected to each of the plurality of first storage sections 50. The connecting member 51 may be omitted. By forming the connecting member connected to each of the plurality of first storage sections 50 from a porous body, the liquid heat transfer medium stored in each of the plurality of first storage sections 50 can be distributed relatively evenly.

[0069] [Variation 4] In the above-described embodiment, the gas flow section 30 is a substantially flat member, and is provided with convex portions that contact each of the pair of liquid flow sections, with a concave portion formed on one main surface at the position where the convex portion is formed on the other main surface, and a concave portion formed on one main surface at the position where the convex portion is formed on the other main surface. The shape of the gas flow section is not limited to this. It is sufficient that a space is formed through which the gaseous heat transfer medium can pass, and it is sufficient that the volume of the space through which the gaseous heat transfer medium can pass accounts for approximately 10% of the total volume of the gas flow section.

[0070] FIG. 14 is a diagram illustrating a first modified example of the gas circulation section. FIG. 14 shows a schematic overall view of the modified example of the gas circulation section. The gas circulation section 80 shown in FIG. 14 includes a base 81, a plurality of pillars 82 extending vertically upward from the base 81, and a plurality of branch portions 83 extending in a direction inclined relative to the vertical direction on each of the pillars 82. In the gas circulation section 80 shown in FIG. 14, when the heat medium liquefied in the heat exchange section 60 falls vertically downward, it hits the plurality of branch portions 83 and is retained by the branch portions 83. The liquid heat medium retained in the branch portions 83 flows along the surfaces of the pillars 82 and the branch portions 83 and moves to the liquid circulation section 40 that is in contact with the gas circulation section 80. Meanwhile, the gaseous heat medium passes between adjacent pillars 82 and moves vertically upward. This allows the gas flow section 80 to move the gaseous heat transfer medium to the heat exchange section 60, and also to receive the liquid heat transfer medium falling from above in the vertical direction and supply it to the liquid flow section 40.

[0071] FIG. 15 is a diagram illustrating a second modified example of the gas circulation section. FIG. 15 shows a cross-sectional view of the modified example of the gas circulation section. The gas circulation section 90 shown in FIG. 15 has a bag-shaped rib 91 at the portion that contacts the liquid circulation section 40. Specifically, the vertically lower side of the rib 91 is formed to extend horizontally, making it easier to catch the liquid heat transfer medium falling from above in the vertical direction. This allows the gas circulation section 90 to supply the liquid heat transfer medium falling from above in the vertical direction to the liquid circulation section 40.

[0072] [Variation 5] In the above-described embodiment, the fluid circulation part 40 is in contact with the surface 21, 21a of the battery cell 20 having a substantially rectangular parallelepiped shape, which has the largest area. However, the surface with which the fluid circulation part comes into contact with the battery cell is not limited to this. Furthermore, the shape of the battery cell is not limited to a substantially rectangular parallelepiped shape, and may be, for example, a substantially cylindrical shape or a substantially pouch-shaped shape.

[0073] [Variation 6] In the above-described embodiment, the heat exchanger 60 includes the spacer 62 having the wall portion 62b formed of a porous body, and the wall portion 62b is in contact with the refrigerant flow portion 61 through which the refrigerant flows. The configuration of the heat exchanger 60 is not limited to this. It is sufficient that the heat exchanger 60 has the function of cooling and liquefying the gaseous heat medium.

[0074] [Variation 7] In the above-described embodiment, the secondary battery 1 includes the case 10, the plurality of battery cells 20, the plurality of gas flow sections 30, the plurality of liquid flow sections 40, the heat exchange section 60, as well as the heater 12, the heat medium collector 73, the connecting member 51, the intermediate member 71, the distributor 72, and the like. The configuration of the secondary battery is not limited to this. It is sufficient if the secondary battery includes the case 10, the plurality of battery cells 20, the plurality of gas flow sections 30, the plurality of liquid flow sections 40, and the heat exchange section 60, and can cool the battery cells 20 using the heat of vaporization that occurs when the liquid heat medium changes phase to the gas heat medium in the liquid flow sections 40 that are arranged on the surfaces 21, 21a of the battery cells 20.

[0075] This aspect has been described above based on embodiments and modifications. However, the above-described embodiments are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0076] <Application example 1> A secondary battery, Case and a plurality of battery cells housed inside the case and arranged side by side in a horizontal direction; a heat medium for cooling the battery cells; a gas flow section through which a gaseous heat transfer medium flows, the gas flow section being disposed between two adjacent battery cells; a liquid circulation section formed of a porous body and through which a liquid heat transfer medium flows, the liquid circulation section being disposed between the gas circulation section and the battery cell and in contact with a surface of the battery cell; a heat exchange unit that is disposed vertically above the gas flow unit and liquefies the gaseous heat medium discharged from the gas flow unit, Secondary battery. <Application example 2> The secondary battery according to Application Example 1, the liquid circulation portion is disposed between each of two adjacent battery cells and a gas circulation portion disposed between the two battery cells, The secondary battery further comprises: a first storage section for storing a liquid heat transfer medium, the first storage section being disposed vertically below the gas flow section and sandwiched between the pair of liquid flow sections; The first storage section is formed of a porous body and is connected to a vertically lower end of the liquid circulation section. Secondary battery. <Application example 3> The secondary battery according to Application Example 1 or Application Example 2, the plurality of battery cells, the gas flow section, and the liquid flow section form a battery stack; The secondary battery further comprises: a support portion that supports the battery stack inside the case so that the battery stack is spaced apart from a bottom surface and a side surface of the case; a second storage portion configured to store a liquid heat transfer medium, the second storage portion being formed by a bottom surface and a side surface of the case on a vertically lower side of the battery stack; a heating unit that heats the liquid heat medium stored in the second storage unit to generate a gaseous heat medium, the gas flow section has a groove that discharges a portion of the liquid heat medium stored in the first storage section to the second storage section, the gaseous heat medium generated in the second storage section passes between the battery stack and a side surface of the case, and moves vertically upward of the battery stack, whereby the gaseous heat medium is liquefied by the heat exchange section; The heat medium liquefied by the heat exchange unit flows through the liquid circulation unit. Secondary battery. <Application Example 4> The secondary battery according to any one of Application Examples 1 to 3, A plurality of the first storage sections are provided, The secondary battery further comprises: A connecting portion connected to each of the vertically lower ends of the plurality of first storage portions, the connecting portion being formed of a porous body. Secondary battery. <Application example 5> The secondary battery according to any one of Application Examples 1 to 4, The gas flow section is It has a substantially plate shape, a protrusion that contacts the liquid flow portion is formed on each of the pair of main surfaces; a recessed portion is formed on one main surface at a position where the protruding portion is formed on the other main surface; a recessed portion is formed on one of the main surfaces at a position where the protruding portion is formed on the other main surface; the inside of the recess formed on one main surface and the inside of the recess formed on the other main surface are in communication with each other along the vertical direction; Secondary battery. <Application Example 6> The secondary battery according to any one of Application Examples 1 to 5, The battery cell has a substantially rectangular parallelepiped shape, the liquid circulation portion is in contact with the surface having the largest area among a plurality of surfaces of the battery cell; Secondary battery. <Application Example 7> The secondary battery according to any one of Application Examples 1 to 6, the heat exchange unit has a refrigerant flow portion through which a refrigerant supplied from an external source flows, and a spacer in contact with the refrigerant flow portion; The spacer is a flow path forming portion that is disposed vertically above the gas flow portion and forms a heat medium flow path through which the heat medium in the gas state passes; a wall portion formed of a porous body, the wall portion being in contact with the refrigerant flow portion and liquefying the gaseous heat medium passing through the heat medium flow path; Secondary battery. <Application Example 8> The secondary battery according to any one of Application Examples 1 to 7, The liquid flow section includes a plurality of the liquid flow sections, The secondary battery further comprises: an intermediate portion formed of a porous body and disposed between the heat exchange portion and the plurality of liquid circulation portions; The intermediate portion is the spacer is in contact with a vertically lower end of the wall portion and a vertically upper end of each of the plurality of liquid circulation portions, an opening formed on a vertically upper side of the gas flow section and communicating with the heat medium flow path; Secondary battery. <Application Example 9> The secondary battery according to any one of Application Examples 1 to 8, The gas flow portion is formed of an insulating material. Secondary battery. [Explanation of symbols]

[0077] 1…Secondary battery 1a...Battery stack 9...Connecting channel 10…Case 10a...Bottom of the case 10b...Side of the case 12...Heater 20...Battery cell 21, 21a...Surface of battery cell 30, 80, 90...Gas flow section 30b…Groove 33, 34...Main surfaces of the gas flow section 331a, 332a, 341a, 342a...convex parts 331b, 332b, 341b, 342b...recesses 40...Liquid distribution section 41a, 42a, 43a...vertical lower end of the liquid flow section 50...First storage section 50a...vertical lower end of the first storage section 51...connecting member 52...Second storage section 60...Heat exchange section 61...Refrigerant distribution section 62...Spacer 62a...flow path forming portion 62b…Wall part 71...Intermediate part 72a…Aperture 731...Collection section

Claims

1. A secondary battery, Case and a plurality of battery cells housed inside the case and arranged side by side in a horizontal direction; a heat medium for cooling the battery cells; a gas flow section through which a gaseous heat transfer medium flows, the gas flow section being disposed between two adjacent battery cells; a liquid circulation section formed of a porous body and through which a liquid heat transfer medium flows, the liquid circulation section being disposed between the gas circulation section and the battery cell and in contact with a surface of the battery cell; a heat exchange unit that is disposed vertically above the gas flow unit and liquefies the gaseous heat medium discharged from the gas flow unit, Secondary battery.

2. The secondary battery according to claim 1, the liquid circulation portion is disposed between each of two adjacent battery cells and a gas circulation portion disposed between the two battery cells, The secondary battery further comprises: a first storage section for storing a liquid heat transfer medium, the first storage section being disposed vertically below the gas flow section and sandwiched between the pair of liquid flow sections; the first storage portion is formed of a porous body and is connected to a vertically lower end of the liquid circulation portion; Secondary battery.

3. The secondary battery according to claim 2, the plurality of battery cells, the gas flow section, and the liquid flow section form a battery stack; The secondary battery further comprises: a support portion that supports the battery stack inside the case so that the battery stack is spaced apart from a bottom surface and a side surface of the case; a second storage portion configured to store a liquid heat transfer medium, the second storage portion being formed by a bottom surface and a side surface of the case, below the battery stack in the vertical direction; a heating unit that heats the liquid heat medium stored in the second storage unit to generate a gaseous heat medium, the gas flow section has a groove that discharges a portion of the liquid heat medium stored in the first storage section to the second storage section, the gaseous heat medium generated in the second storage section passes between the battery stack and a side surface of the case, and moves vertically upward of the battery stack, whereby the gaseous heat medium is liquefied by the heat exchange section; The heat medium liquefied by the heat exchange unit flows through the liquid circulation unit. Secondary battery.

4. 4. The secondary battery according to claim 2, wherein: A plurality of the first storage sections are provided, The secondary battery further comprises: A connecting portion connected to each of the vertically lower ends of the plurality of first storage portions, the connecting portion being formed of a porous body. Secondary battery.

5. 3. The secondary battery according to claim 1, The gas flow section is It has a substantially plate shape, a protrusion that contacts the liquid flow portion is formed on each of the pair of main surfaces; a recessed portion is formed on one main surface at a position where the protruding portion is formed on the other main surface; a recessed portion is formed on one of the main surfaces at a position where the protruding portion is formed on the other main surface; the inside of the recess formed on one main surface and the inside of the recess formed on the other main surface are in communication with each other along the vertical direction; Secondary battery.

6. 3. The secondary battery according to claim 1, The battery cell has a substantially rectangular parallelepiped shape, the liquid circulation portion is in contact with the surface having the largest area among a plurality of surfaces of the battery cell; Secondary battery.

7. 3. The secondary battery according to claim 1, the heat exchange unit has a refrigerant flow portion through which a refrigerant supplied from an external source flows, and a spacer in contact with the refrigerant flow portion; The spacer is a flow path forming portion that is disposed vertically above the gas flow portion and forms a heat medium flow path through which the heat medium in the gas state passes; a wall portion formed of a porous body, the wall portion being in contact with the refrigerant flow portion and liquefying the gaseous heat medium passing through the heat medium flow path; Secondary battery.

8. The secondary battery according to claim 7, The liquid flow section includes a plurality of the liquid flow sections, The secondary battery further comprises: an intermediate portion formed of a porous body and disposed between the heat exchange portion and the plurality of liquid circulation portions; The intermediate portion is the spacer is in contact with a vertically lower end of the wall portion and a vertically upper end of each of the plurality of liquid circulation portions, an opening formed on a vertically upper side of the gas flow section and communicating with the heat medium flow path; Secondary battery.

9. 3. The secondary battery according to claim 1, The gas flow portion is formed of an insulating material. Secondary battery.

Images